Reference / Paper · 2006

Peak of Flight #169: Using SMARTSim 2.0's Batch Processing Feature Part 2

Apogee Components' Peak of Flight newsletter, issue 169 (2006-10-24).

Author: Tim Van Milligan / Apogee Components
Year: 2006
Type: Reference / Paper
Credit: Apogee Components, Inc. (Colorado Springs, CO) — Peak of Flight newsletter

peak-of-flight
apogee-components
model-rocketry

Apogee Components' Peak of Flight newsletter, issue 169 (2006-10-24).

I S S U E 1 6 9 - O C T O B E R 2 4 , 2 0 0 6 Using SMARTSim 2.0 Advantages for TARC Competitors Part 2 INSIDE: • Gain An Edge In TARC With The SMARTSim Software • How-To Overcome the Problem of Positioning LARGE Self-adhesive Decals • Web Site of the Week • Apogee's New Rocketry Grant Program • The Latest NAR Education News 1130 Elkton Drive, Suite A Colorado Springs, Colorado 80907 USA www.ApogeeRockets.com e-mail: [email protected] phone: 719-535-9335 fax: 719-534-9050 I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 Advantages of Batch Processing Using SMARTSim v2.0 Part 2 Figure 1. Hypothetical TARC Design by Ken Karbon Introduction In the last Peak-of-Flight newsletter, I introduced the batch processing feature of SMARTSim 2.0. It allows you to run hundreds of RockSim simulations with a simple input ﬁle. Instead of haphazard guessing and checking the results, SMARTSim sets up systematic combinations for analysis. In this article, I will show how to use SMARTSim batch processing to help design a rocket to compete in TARC 2007. Two of the contest’s requirements are ideal for study with RockSim and SMARTSim – achieve 850 ft maximum altitude AND a total ﬂight duration of 45s. Some of the methods I use in this example are a bit advanced for TARC students and require other engineering tools, but your math and science teachers can probably help with similar, yet simpler approaches. Use the power of simulations to give you that competitive edge. Designed Experiment for a TARC Rocket To begin, I created a hypothetical payloader design to carry the required egg and altimeter as shown in Figure 1. Next, I need to deﬁne the critical parameters that might affect the ﬂight performance and use them as control factors. For this study, I chose four basic rocket features that can be varied with RockSim - the payload tube diameter, the payload mass object, the parachute diameter, and the engine. The output factors are maximum altitude and ﬂight duration. Table 1 shows the definition of my experiment and a range of values for the control factors. These factors are selected from the rkt ﬁle and written to a batch ﬁle with SMARTSim. �� Table 1. Experiment Design As an engineer, I have very sophisticated Design of Experiments (DOE) software which I used to set up my experiment. I created 121 runs to deﬁne my design space within the ranges given above. I copied the resulting run matrix into the batch ﬁle with an Excel spreadsheet as shown in Figure 2. Note that when varying payload outside diameter, I must also change the inside diameter along with the nose cone base diameter and transition front diameter in order to keep the rocket “together” so that RockSim can properly compute mass, Cp, and Cd. Those extra columns are deﬁned in the batch ﬁle as well. Figure 2. Batch File for TARC Study (121 Runs) continued on page 4 About this Newsletter You can subscribe “FREE” to receive this e-zine at the Apogee Components web site (www.ApogeeRockets.com), or by sending an e-mail to: [email protected] with “SUBSCRIBE” as the subject line of the message. A P O G E E Page 2 R O C K E T S I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 Apogee Rocketry Grant Program Apogee Components, Inc. is pleased to announce the ﬁrst in a yearly grant program geared toward model rocketry education organizations! The rules are simple: 1. Entrants must submit an essay to Apogee. There is no length requirement for the essay. 2. Any club, organization, school program, etc. is eligible for entry. This would include rocketry clubs or prefectures, 4H, scouts, etc. 3. The content and purpose of the essay is as follows: • If we gave you $300.00, How would you use it to impact the rocketry community? • How many people you think it will reach? • How many people are involved in the organizing and running of the event? • How big of an effect it will have on the rocketry community? 4. One of the biggest things to keep in mind when composing your essay is, “How is what I am planning unique”? There will be only one winner and recipient of the grant, which is $300.00 toward any order with Apogee Components. The deadline for entry is November 30, 2006. The grant winner will be announced on January 1, 2007. What a great way to start off the new year! send essay to 1130 Elkton Drive Suite A Colorado Springs CO 80907 or [email protected] http://www.apogeerockets.com/october_special.asp A P O G E E R O C K E T S Page 3 I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 continued from page 2 I then ran this batch ﬁle in SMARTSim. The 121 calculations took about 6 minutes on my Pentium 4-2.6 GHz PC. Only with batch processing can you attempt such a large number of “what-if” scenarios. It would take you hours upon hours to perform these same simulations by manually adjusting the parameters and pressing the “launch” button in the RockSim GUI! And ﬂight tests? Forget about it. To run this experiment with hardware tests would be costly, time-consuming, and downright impossible. Save your precious prototypes and building materials for validation ﬂights and ﬁnal tweaking after the simulations. From the batch output data, I performed a statistical technique called ANOVA (ANalysis Of VAriance) to understand the contributions of each of the control factors. Understandably, the choice of engine had the most effect on the altitude and ﬂight duration, with the other factors and interactions having less impact (Figure 3). This result reveals where your design efforts should be focused to achieve the target. Contribution 0% 20% 40% 60% 80% 100% EngineCode PayloadMass EngineCode * ChuteDia ChuteDia EngineCode * PayloadMass PayloadOD ChuteDia * PayloadMass Figure 3. Flight Duration ANOVA EngineCode * PayloadOD Lastly, I used Excel programming to analyze the TARC objectives with a numerical model built from ChuteDia * PayloadOD the experiment data. For a unique solution to the two outputs (altitude and time), I simultaneously solved for two of the unknowns – payload mass and chute diameter (Table 2). With the surrogate Excel model, I can solve and optimize multiple parameters without having to guess and check in the RockSim GUI. As a conﬁrmation, I plugged in my predicted solution to the four PayloadMass * PayloadOD A P O G E E Page 4 variables back into RockSim and obtained the desired result shown in Table 3. Payload OD Payload Mass Chute Diagram in g in 3 426.7738607 30.21577122 Engine Code Max Altitude Time To Landing S ft F52 850.0000009 45.0000002 Table 2. Solution to the TARC Design from Experiment Model Max data values: • Maximum altitude: 850.60256 Ft. Landing data • Time to landing: 45.069 Sec. Table 3. Conﬁrmation RockSim Simulation Details Summary Of course, this hypothetical design does not take into account all the other important factors when building and ﬂying a competition rocket. I purposely left out a lot of the details, because TARC students must create their own designs without help from others. This example is intended to show how engineering problems are solved in practice using efﬁciently-designed experiments and not brute-force trial and error. The advanced numerical techniques I used here would not be possible without the large number of RockSim simulations that I easily generated with SMARTSim v2.0. About the Author Ken Karbon is a rocketeer from Michigan and the developer of SMARTSim. He holds a Masters Degree in Mechanical Engineering and works as an aerodynamicist in the auto industry, specializing in CFD simulation. For more information email [email protected] R O C K E T S I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 ® N A R NEWS Alabama Girl Scout Space Initiative The NASA Explorer Institutes (NEI) program “Growing the NASA-Girl Scouts of the USA (GSUSA) Relationship Through Professional Development” is producing a rocketry curriculum at the MSFC with NAR. This is being implemented in Alabama where Scout leaders are trained in rocketry basics by NAR members to teach their girls how to perform science activities and earn a merit patch. It hopes to reach up to 22,000 Girl Scouts in the state. The objectives are: to create a rocketry patch program that is age appropriate for Brownie, Junior and Senior Older Girl Levels, to design and conduct a day-long professional development to train staff to support ‘space day’ and related events, and to utilize NAR mentors to provide leadership and support for Girl Scout participation in Team America Rocketry Challenge (TARC). Once established and approved, the rocketry patch will be offered to Scout Councils nation wide. See the webpage at: http://education.nasa.gov/divisions/informal/overview/ F_2005_Explorer_Institutes_List.html Team America Rocketry Challenge Registration Opens The 2007 Team America Rocketry Challenge registration opened September 6, and closes November 15, or whenever 750 teams are registered, whichever comes ﬁrst. Each year over 7000 students in 7th through 12th grade across the US measure themselves against a ﬂight performance challenge that requires aerospace engineering and model rocketry skills. Everything is in place to begin the ﬁfth year of this program that is dedicated to building the next generation of U.S. aerospace professionals. The challenge is for student teams to design, build, and ﬂy a model rocket that carries a raw egg payload and returns it unbroken, while meeting a spe- A P O G E E ciﬁc ﬂight performance target. This year the target is to reach 850 feet, and have the ﬂight last 45 seconds from liftoff to egg touchdown. The teams make a local ‘qualiﬁcation’ ﬂight, and then progress to the national ﬂyoff in Great Meadows, Virginia in May 2007. Over $60,000 in cash, savings bonds, and other prizes are awarded each year by sponsors. TARC is sponsored by the Aerospace Industries Association (AIA), NAR, in partnership with NASA, the Dept. of Defense, American Association of Physics Teachers, and 39 AIA member companies. To learn more about TARC, please sign up at the the web site below. The site contains the contest application, rules, team handbook, information handbook, schedule, and much more. http://www.rocketcontest.org Visually Impaired Students Experience Model Rocketry Twelve visually impaired and blind high school students had an opportunity to explore careers in rocketry in the Rocket On! program, as part of a partnership between NASA and the National Federation of the Blind. The students participated in a week-long rocket science camp, July 14-22, at the Federation’s Jernigan Institute in Baltimore and NASA’s Wallops Flight Facility, Wallops Island, VA. The program has now ﬁnished its third year. As part of the workshop, the students learned to use MathTrax software, a calculator that enables them to visualize data by translating information into an easily accessible text or audio description. This free MathTrax computer application may be downloaded for Windows and Macintosh platforms at: http://prime.jsc.nasa.gov/mathtrax/bviDownload.htm Hopefully, this opportunity will be available for visually impaired students next year as well, and we will keep you updated about the application process in this newsletter. For more information, see the press release below. http://www.nasa.gov/home/hqnews/2006/jul/HQ_ 06277_NASA_aids_students_ﬁnal.html R O C K E T S Page 5 I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 Customer Testimonial My order arrived promptly with the contents in excellent condition. Again, it’s been a pleasure doing business with Apogee Components and I look forward to future dealings with your company. I would like to offer some additional feedback on three points that I believe are of particular credit to Apogee. As your goal is to keep the hobby of model rocketry thriving, mine is to endorse and support such efforts as a customer and fellow rocketry enthusiast. My points are as follows: 1) Customer Service - Apogee has done a fantastic job of ensuring customer satisfaction through its commitment to quality, responsiveness, and courtesy. Where other companies have sacriﬁced these fundamentals as a cost-cutting measure, and adopted a “nickel and dime” philosophy, Apogee lives up to its name in its endeavor to develop rewarding relationships with its customers. 2) Integrated Experience - Through its offerings of books, software, kits, and other materials related to the hobby of rocketry, Apogee has brought to market a broad and rich experience that promises years of learning and enjoyment for anyone with interest in the ﬁeld. 3) Attention to Detail - The attention to detail evident in Apogee’s kits, in particular the Saturn 1B and V models, is world class and unique in an industry where a trend toward simplistic, mass-produced toys seems to have taken hold in recent years. In addition to the models themselves, Apogee has gone the extra mile with its multimedia instructions, detailed painting guides, posters, and other goodies. These extras have taken much of the frustration out of building complex rockets without diminishing the challenge and reward. Bravo! I am very happy with my Saturn 1B kit and will be purchasing a Saturn V upon completion. I’ll also be adding a number of books and the RockSim software to my orders in the coming months. I would be happy to recommended Apogee Components to others. With regard to the RockSim software, it’s a stellar product and perhaps the only one of its kind available to hobbyists. I’ve shown it to several co-workers involved in ballistics/aerodynamics R&D for the US Navy and they were impressed. - Bryan Vandrovec by the average thrust level that is printed on the label. For example, a C6 engine has a maximum power of 10 N-s, and has an average thrust of 6 Newtons. Therefore, the burn time Every model rocket engine has a designation code printis 10 divided by 6, which equals 1.67 seconds. Burn time and ed on it that gives speciﬁc information. The ﬁrst letter in the average thrust are important to modelers who want the rocket designation code tells you the power level. For example, a C to ﬂy to the highest altitudes. The longer the burn time, the engine will lift a model approximately twice higher the model will travel. This is beTotal Impulse (Power) as high as a B engine, and four times higher cause a slow speed rocket has less drag Classification than an A engine. The ﬁrst number in the code than a high speed model, so it can coast Average Thrust Level tells you the average thrust produced by the longer. (Newtons) engine. This level is expressed in Newtons. The last number in the designation code In our example, the C6-5 engine produces an is the time in seconds between propellant average of 6 Newtons of thrust over its burn burnout and when the ejection charge ﬁres. time. Light models require a low average A C6-5 has a ﬁve-second delay before the Delay Time thrust to lift them and heavy rockets require a ejection charge ﬁres to push the parachute (Seconds) high average thrust to lift the them. out of the rocket. Choose this delay time From this ﬁrst number in the designation very carefully. The delay you pick depends code you can also determine the approximate burn time. To on the mass of the model, how much drag it will produce, the do this, divide the total impulse at which the engine is rated angle at which it is launched, and how stable it is. DEFINING MOMENTS C6-5 A P O G E E Page 6 R O C K E T S I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 ® TIP OF THE FIN Have you ever been working with self-adhesive decals only to have them develop those nasty bubbles underneath? This can be very frustrating, indeed! Here is a great tip to help get those self-adhesive decals on correctly the ﬁrst time. To begin, you will need a bowl and some liquid dish soap. Put a drop or two in the bowl and add some warm water as you can see in picture 1. You don’t want a lot of suds, so be sparing on the soap. Now take a decal and pull the backing off as seen in ﬁgure 2. You will then need to dip the decal in the soapy solution that you made up. It won’t need to soak; just dip it in and take it out, as long as it gets wet (I know this A P O G E E sounds strange, but bear with me). This is shown in picture 3. After taking the decal out, go ahead and position it where you want on your model. Don’t worry about not placing it exactly the ﬁrst time. After you move the decal into the ﬁnal position that looks best to you, take a paper towel and carefully dry up the suds that are oozing out. It’s best to hold on to the decal at one side so that it doesn’t move (see picture 4). After you initially soak up the majority of the water, take a dry paper towel and press out the rest of the water and air bubbles with it in a “squeegee” fashion. Picture 5 shows the ﬁnished product and as you can see, it makes the decal look very nice. It is recommended to put on a clear coat of paint to seal it down. R O C K E T S Page 7 I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 RockSim: The Software That Lets You Design Amazing Rockets! RockSim is the leading software for designing rockets, and ﬁnding out how high they will ﬂy. Here is what rocketeers are saying about it: “After a lot of searching on the Net, Rocksim is the best rocketry simulation software I have seen. In terms of sophistication, ‘Rocksim’ is to ‘VCP’ as ‘VCP’ is to ‘cutting out pieces of cardboard’.” -- Brian Crosse Launch Success Begins with RockSim Dream It Design It n Simulate It n Build It n Fly It. n n Space Foundation certiﬁed as an excellent teaching aid. www.RockSim.com For further information, call Apogee Components at: 719-535-9335. Mention this ad for a free CD-ROM of RockSim how-to videos. QUESTION AND ANSWER CORNER Dave Miller asks, “I ordered your book “69 Science Fair Projects” (http://www.apogeerockets.com/science_ fair_book.asp) which I am very pleased with. My daughter would like to do the project on the optimal weight of a model rocket (so that it will reach its optimal altitude). She found in a book that an “ideal” real rocket should be 91% propellant, 3% tanks, engines, hardware, and 6% people and instruments. These percentages seem way off for a model rocket. Do you have similar percentages for model rockets or could you point us to a source(s) that might have this information”? Mr. Rocket says, “There are no good formulas for model rockets. It all depends on the size and shape of the rocket, and the type of rocket motors that you use. What most modelers do is to use the RockSim software to calculate the optimum mass of the particular design and A P O G E E Page 8 motor combination. With a click of the button, you can get the answer. For most typical model rockets, it is physically impossible to make the rocket light enough, as the weight of the motor case is more than the optimum mass allowable. But there are some very tiny motors, like the Estes A10-3T motor where it is possible to build the rocket at the optimum mass. It is easier to use big motors when doing optimum mass studies. The drawback is that they are more expensive." Download the free demo version of RockSim from my web site. You’ll ﬁnd it at: http://www.apogeerockets.com/rockSim_demo.asp You might also be interested in the article about optimum mass that can be found in Technical Publication #15 which can be found at: http://www.apogeerockets.com/technical_publications.asp”. R O C K E T S I S S U E 1 6 9 - O C T O B E R 2 4, 2 0 0 6 Page 1 of 1 If you want to build REALLY big rockets try these two great books from Apogee Space Books www.apogeebooks.com 905 637 5737 "Apogee Books" is not afﬁliated with Apogee Components. But they do sell some nifty space books, and we do recommend them. Web Sites Worth Visiting Do you need to keep up on your space-related news? Then Spacetravels is the website for you! At http://www.spacetravels.gr/html/index_gb.html you will ﬁnd the latest and the greatest on topics such as space missions, tourism, technology, health, and science, just to name a few. You may be familiar with the Ansari X-Prize; this site has the details about Anousheh Ansari. Anousheh is the ﬁrst female space tourist and has dreamed of space exploration since childhood. Her family provided the title sponsorship for the Ansari X Prize, a $10 million cash award for the ﬁrst non-governmental organization to launch a reusable manned spacecraft into space twice within two weeks. This feat was accomplished in 2004 by legendary aerospace designer Burt Rutan. Also in the news is the new spaceport in New Mexico. "This state has worked hard to bring us to their exciting new spaceport facility,” stated Will Whitehorn, President of Virgin Galactic. “The state has several factors that make it an ideal operations base: climate, free airspace, low population density, high altitude, and stunning scenery. Our team was highly impressed by the professionalism and the competitive pitch the state and its advisors developed”. Take a look at this and see what’s up in our corner of the universe. Anousheh Ansari A P O G E E R O C K E T S Page 9